UNIX for Advanced & Expert Users

sed '/select/,/table_name/!d' file1.txt

sed '/select \*/,/from/!d' file1.txt

       Unlike grep, egrep, or fgrep, cgrep allows the matching of patterns,
       delimiters, or trail_patterns that may span multiple lines of text
       through the use of literal newline characters.  The section, MULTI-LINE
       MATCHING, explains this in more detail.

-- excerpt from man cgrep

echo "a
###select *
from table_name####
sein
select *
egeg
from table_name###" |awk -v RS='select \\*$\nfrom table_name' '{print RT}'
select *
from table_name